The present invention relates to combustion engines for scale models that utilize glow plugs. More particularly, the present invention relates to an energizing device for starting glow plug equipped engines.
Engines used in model airplanes, cars, boats, etc. are referred to as xe2x80x9cglow-ignitionxe2x80x9d engines because they rely on glow plugs for their operation. The glow plugs, which are located within a combustion chamber of the engines, are heated to ignite an air/fuel mixture within the combustion chamber.
In order to cause initial combustion within the combustion chamber of the engine, normally one pole of a small voltage battery is connected to the center pole of the glow plug and the other pole of the battery is connected to the glow plug body or to the engine head for completing an electrical circuit through the coil element of the glow plug. When the coil element becomes sufficiently hot to cause ignition of the fuel/air mixture within the combustion chamber the engine may be started. After sufficient engine heat is developed within the combustion chamber to keep the coil element hot, the battery or power source may be disconnected from the glow plug, and the engine heat itself will be sufficient to sustain operation.
There are many ways to connect battery leads to the glow plug of a combustion engine. One of the most common ways is the use of lead wires having alligator type clips associated therewith. With such an arrangement, one alligator clip is connected to the center pole of the glow plug and the other is connected to some metallic portion of the engine head. This method, while workable is undesirable and can even be dangerous. Unless great care is taken, the alligator clips may both come into contact with the cylinder head, thereby causing an electrical short. Further, usually associated with an engine of this sort is a fast turning propeller which may cause damage upon coming into contact with the electrical leads. Further yet, it is desirable for the leads to be disconnectable with one hand since the other hand is needed to hold the model in place after the engine is started.
Other attempts have been made to develop a single unit connector which connects one lead of the battery through the center pole of the glow plug and the other lead to somewhere on the engine body to complete the circuit. However, most of these units have been unsuccessful in withstanding the vibration normally associated with starting of a model airplane type engine.
U.S. Pat. No. 6,276,325 to Arlton discloses a glow plug connection for model engines that comprises a plug clip that can be attached and removed from a glow plug with one hand.
U.S. Pat. No. 4,405,890 to Hicks, Jr. discloses a rechargeable glow plug energized that includes a Headlock connector and a rechargeable battery in a single hand held assembly.
While the art of glow-ignition engines has advanced so that glow plugs can now be connected and disconnected from batteries for engine start-up, the art has failed to address a situation which arises when one attempts to start a cold engine or an engine having an air-to-fuel ratio that needs to be adjusted.
When starting a cold glow-ignition engine it is not uncommon for an engine to start with a battery connected to a glow plug and then fail, because of being cold, when the battery is disconnected. In other situations, it is not uncommon for an engine to start with a battery connected to a glow plug and then fail when the battery is disconnected, while trying to adjust the fuel/air ratio.
The present invention provides an energizing device for starting glow plug equipped engines which can prevent premature failure of the engines during start-up operations.
According to various features, characteristics and embodiments of the present invention which will become apparent as the description thereof proceeds, the present invention provides a glow plug energizing device which includes:
a glow plug connector configured to be releasably coupled to a glow plug;
at least one battery for supplying electrical energy to the glow plug connector;
a housing containing the at least one battery;
an electrical lead coupled between the housing and the glow plug connector; and
a first manual switch coupled to the electrical lead for selectively applying electrical energy from the at least one battery to the glow plug connector.
The present invention further provides a method of starting a glow-ignition engine which involves the steps of:
a) providing a glow-ignition engine having a glow plug;
b) providing a glow plug energizing device which includes:
a glow plug connector configured to be releasably coupled to a glow plug;
at least one battery for supplying electrical energy to the glow plug connector;
a housing containing the at least one battery;
an electrical lead coupled between the housing and the glow plug connector; and
a first manual switch coupled to the electrical lead for selectively applying electrical energy from the battery to the glow plug connector;
c) coupling the glow plug connector to the glow plug;
d) activating the first manual switch to energize the glow plug;
e) starting the glow-ignition engine;
f) deactivating the first manual switch;
g) removing the glow plug connector from the glow plug.